You can't run a business or anything else on a theory.

His recent works focus more on political theory and cultural issues.

Our understanding of the world around us is based on theory.

Children here start school late on the theory that they will learn to love learning through play.

Other important works on the theory of art were to follow.

"It means their approach to politics doesn't rest on theory in the same way."

His research has focused on international law, political theory, and human rights.

I'll let you in on a little theory of mine.

Many studies have been conducted on the theory of the will to live.

Oh, of course, they never thought anyone would act on their theories!